[Pw_forum] Problems with integrated charge for a large supercell relaxation

JR Schmidt schmidt at chem.wisc.edu
Fri Nov 21 22:02:46 CET 2008

Just to follow up on the problem of the integrated charge --
> Your system is treated as an insulator. If for some reason it
> becomes metallic or semimetallic,  you may run into trouble.
> Add a few more bands and a small broadening, just in case.
I went back and verified this system.  Even at the geometry where the 
optimization failed, I took that geometry and did and SCF calculation 
with extra bands.  The band gap (at that geometry ) is 3.1 Ry (as would 
be expected for this strong metal oxide insulator), so I don't think 
that is the problem.

As I mentioned in the initial email, it is also odd that I can restart 
the SCF or optimization from the 'failed' geometry and go for quite a 
few optimization cycles before another crash
> Note that
> K_POINTS Gamma
> (uses "Gamma tricks") will be faster and take less memory
Fantastic!  I was looking for a different (gamma-specific )executable, 
but I couldn't find one.  Now I know why.

J.R. Schmidt
Assistant Professor of Chemistry
Room 8305D
Department of Chemistry
University of Wisconsin-Madison
1101 University Ave
Madison, WI 53706

Phone: (608) 262-2996
Fax: (608) 262-9918
E-mail: schmidt at chem.wisc.edu

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